From c9441c291662286a67a72f454f3e1b633aad3f78 Mon Sep 17 00:00:00 2001 From: Danny Al-Gaaf Date: Fri, 22 Mar 2019 01:37:56 +0100 Subject: [PATCH] doc: fix LRC documentation Recovery from a failure in jerasure need only k reads and not k+m-1. Signed-off-by: Danny Al-Gaaf --- doc/rados/operations/erasure-code-lrc.rst | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/doc/rados/operations/erasure-code-lrc.rst b/doc/rados/operations/erasure-code-lrc.rst index eeb07a385758f..348fc164d003a 100644 --- a/doc/rados/operations/erasure-code-lrc.rst +++ b/doc/rados/operations/erasure-code-lrc.rst @@ -5,14 +5,14 @@ Locally repairable erasure code plugin With the *jerasure* plugin, when an erasure coded object is stored on multiple OSDs, recovering from the loss of one OSD requires reading from all the others. For instance if *jerasure* is configured with -*k=8* and *m=4*, losing one OSD requires reading from the eleven +*k=8* and *m=4*, losing one OSD requires reading from the eight others to repair. The *lrc* erasure code plugin creates local parity chunks to be able to recover using less OSDs. For instance if *lrc* is configured with *k=8*, *m=4* and *l=4*, it will create an additional parity chunk for every four OSDs. When a single OSD is lost, it can be recovered with -only four OSDs instead of eleven. +only four OSDs instead of eight. Erasure code profile examples ============================= -- 2.47.3